I love hitting this shot. It rarely works to win the point, but it is fun to go for it. One time, I actually hit one for a winner against a solid player who totally melted down cuz he was that irritated over it ...
Anyway, the big mistake I made with this one is not keeping my head on the ball THE WHOLE TIME!!!! I would inevitably pull my head around to see if it worked or not.
Another thing, get there early and then use super mini steps to position yourself over top of the ball as it falls. Another "cheater" hint in hitting it is that I don't always have both feet on the ground at contact- if hitting right handed, I take a last second mini step with my left foot, which puts me a little more "over" the ball, and giving me a little more groin clearance. This also clears my left leg out of the way of the racquet head which ends up behind the left knee/thigh.
Also, I use a grip a little closer to Continental than Eastern backhand.
A good way to drill this shot is against a wall; give it a ping pong serve (from the ground to the wall) and it will play like a lob over your head.